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Storage cells for internal experiments with Atomic Beam Source at the COSY storage ring

Storage cells for internal experiments with Atomic Beam Source at the COSY storage ring. by Kirill Grigoryev Institut für Kernphysik , Forschungszentrum Jülich, Germany Petersburg Nuclear Physics Institute, Gatchina, Russia. 14.09.2011. ABS beam. Cyclotron beam. Storage cell.

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Storage cells for internal experiments with Atomic Beam Source at the COSY storage ring

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  1. Storage cells for internal experimentswith Atomic Beam Sourceat the COSY storage ring by Kirill Grigoryev Institut für Kernphysik, Forschungszentrum Jülich, Germany Petersburg Nuclear Physics Institute, Gatchina, Russia 14.09.2011

  2. ABS beam Cyclotron beam Storage cell Proposed by W. Haeberli 2nd International Symposium On Polarization Phenomena, Basel, 1966

  3. The first cell. Deuteron, VEPP-3 PINTEX, IUCF-Cooler ANKE, COSY HERMES, DESY Storage cell

  4. p, p, d, d with momenta up to 3.7 GeV/c COSY – COoler SYnchrotron • internal experiments – • with the circulating beam • external experiments – • with the extracted beam

  5. Spectrometer ANKE ANKE at COSY • Magnets • D2 – spectrometer magnet • D1, D3 – beam bending magnets • Detector systems • Positive & Negative • Forward & Backward • Spectator Detectors • Targets • Solid strip • Cluster jet • Polarized gas cell • ( polarized gas jet )

  6. Storage cell to increase target density Lamb-shift polarimeter (LSP)for online polarization measurements Polarized Internal gas Target (PIT) Atomic Beam Source (ABS) Target gas Hydrogen or Deuterium Beam intensity (2 HFS) 8 ∙1016 at/s ABS beam size σ = 2.85 ± 0.42 mm Hydrogen polarization PZ = 0.89 ± 0.01 PZ = - 0.96 ± 0.01 Target density at ANKE jet ~ 1.5 · 1011 at/cm2 cell ~ 2.1 · 1013 at/cm2 talk by M. Mikirtychyants 15 September 2011 talk by R. Engels 13 September 2011

  7. Development of the storage cellsfor internal experimentswith Atomic Beam Sourceat ANKE / COSY

  8. Vacuum chamber Frame with diaphragms or a special diaphragm support XY-table COSY beam Beam profile measurements setup

  9. Scraper F. Hinterberger and D. Prasuhn, NIM A279 (1989) 413. K. Potter, Beam profiles, Yellow Report CERN 85-19, pp.301-317. Measurement at injection

  10. Measurement on flattop (2.65GeV) Transverse fixed storage cell dimensions are 15 x 20 mm2Transverse openable storage cell dimensions are 15 x 12 mm2

  11. Cooling off Cooling on Cooling procedures at COSY At injection energy Stacking injection • 28 stacks with 2s electron cooling • acceleration to 600 MeV after 1 minute • maximum cooling energy < 100 MeV • On the flattop • Stochastic cooling • Minimum energy is cooling is 831MeV

  12. First double pol. experiment (2007) Storage cell & support • storage cell size – 15 x 20 x 390 mm3 • 25 μm thin Al foil (99.95 Al) + 5 μm Teflon coating • high target density • unpolarized gas feeding system LSP below the target chamber • online measurement of the ABS beam polarization Silicon tracking telescope (STT) • measurement of spectator protons nearby the storage cell center (10 mm away from the cell wall)

  13. cell Y - distribution of the particle trajectories XY - distribution of the particle trajectories Achievements in 2007 Acceleration without gas in the storage cell Switching on the gas to feed the storage cell ~7 · 109 polarized deuterons!!! 0 20 50 Time, min Stacking injection 120 injections with 10 s e-cooling Flat top 30 min, to have about 2/3 duty time

  14. RESULTS Polarized target density in the cell dt ~ 2 · 1013 at/cm2 COSY-beam N ~ 7 · 109 d Luminosity in the experiment L ~ 2.5 · 1029 s-1cm-2 Hydrogen polarization in the cell Qy =0.75 ± 0.06 Deuteron COSY-beam polarization Pz ~ 0.51 ± 0.04 → R.Engels - PSTP ’07 proceedings AIP Conf. Proc. 980, 161 (2008) H2 PIT @ ANKE : status 2007 • In 2007 commissioning of the Polarized Internal hydrogen gas • Target at COSY was completed successfully The first 5 weeks production run with hydrogen PIT was performed in October 2009 (Exp. #172.1) Another 7 weeks of data taking with hydrogenPIT in May 2011 (Exp. #205)

  15. PIT @ ANKE in 2009 • Fall 2009 beamtime at ANKE with polarized hydrogen : • source intensity - 8 · 1016 at/s • target density - 1.34 · 1013 at/cm2 • expected density - 1.44 · 1013 at/cm2 (~7% more) • Storage cell configuration: • dimensions 15x20x370 (140+230) mm3 • material 25μm Al + 5μm Teflon

  16. Storage cell for ANKE • not openable storage cell for ANKE experiments

  17. New storage cell • New experiments requires higher density • of the polarized H2 / D2 target • Loosing intensity on the cell walls • Loosing time with stacking injection • Loosing density with fixed storage cell • ANKE needs an openable storage cell

  18. Cell dimensions optimization (1)

  19. Cell dimensions optimization (2)

  20. Cell dimensions optimization (3) 100% ~ 1.34 · 1013 at/cm2 328% ~ 4.40 · 1013 at/cm2

  21. Target chamber and 4 STT

  22. Openable cell and 2 STT

  23. Openable cell

  24. Openable storage cell for ANKE

  25. The opening mechanism was slightlyshifted from its original positionand the storage cell stop movingat the end of the machine development Openable storage cell for ANKE

  26. Conclusion • Fixed storage cell configuration: • dimensions 15x20x370 (140+230) mm3 • material 25μm Al + 5μm Teflon • Atomic hydrogen target density - 1.34 · 1013 at/cm2 • Openable storage cell configuration: • dimensions 11x11x390 (190+200) mm3 • material 25μm Al + 5μm Teflon • Expected atomic hydrogen target - 4.7 · 1013 at/cm2

  27. spare

  28. Target – storage cell with (un)polarized ABS beam Target – ABS jet with unpolarized Hydrogen Target – storage cell with unpolarized ABS beam cell region D2 region ABS-jet region D2 region 3 - jet density, cm - ABS target thickness ~ 2.1 . 1013 cm-2 luminosity ~ 1029 cm-2s-1 target thickness ~ 1013 cm-2 Hydrogen in HFS 1 only target thickness ~ 1.5 . 1011 cm-2 First exp. with storage cell (2006)

  29. Magnetic field along the COSY • and PIT beams was measured • at different D2 currents • (from stand-by to max)

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